| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 46.1 | 36 |
| 2015 | 46.4 | 36 |
| 2014 | 51 | 38 |
| 2013 | 55.3 | 36 |
| 2012 | 54.7 | 34 |
| 2011 | 56.9 | 32 |
| 2010 | 48.9 | 33 |
| 2009 | 39 | 40 |
| 2008 | 46.4 | 34 |
| 2007 | 40.2 | 35 |
| 2006 | 38.6 | 33 |
| 2005 | 31 | 37 |
| 2004 | 26.9 | 38 |
| 2003 | 20.7 | 42 |
| 2002 | 17.8 | 40 |
| 2001 | 18.9 | 40 |
| 2000 | 21 | 36 |
| 1999 | 20.4 | 38 |
| 1998 | 21.1 | 37 |
| 1997 | 21.2 | 40 |
| 1996 | 19 | 43 |
| 1995 | 18.3 | 42 |
| 1994 | 14.7 | 42 |
| 1993 | 12.9 | 41 |
| 1992 | 11.7 | 43 |
| 1991 | 10.4 | 43 |
| 1990 | 10.3 | 46 |
| 1989 | 9.9 | 44 |
| 1988 | 10 | 42 |
| 1987 | 11.7 | 40 |
| 1986 | 11.1 | 36 |